Your point regarding the 'compile time' versus 'run time' distinction is a point well-taken.

From a technical perspective, your point helps to identify and zero in on a key issue. From a communication perspective, it helps to demonstrate how "the law" (TLIA) can creep into even this very discussion.

Perl has no way of knowing that you use ... $main::fee since the usage of $main::fee is not a part of your program yet.

Although the whole "throwaway warnings" example is not my favorite, the point I hoped to illustrate was *precisely* that people can have "inconsistent assumptions" about what constitutes "part of your program yet."

One person can take the (admittedly more complete) assumption that a program is "finished" only after it has compiled, run and terminated. Another person can take the (admittedly more simplistic ... and perhaps even deeply flawed) assumption that a program is "finished" once he or she has written all the source code and saved it to disk.

Because of TLIA, I guess the point is, this kind of "disagreement" (aka divergence of assumptions) does not even get out into the open (what does the word "finished" mean) until: 1) someone proactively asserts "active listening"; or 2) something more "messy" like a contract dispute arises.

I guess the other point is, TLIA is something I (and perhaps others) need to be more keenly aware of in general...